From 1935 until his death in 1951, Artur Schnabel wrote more than 400 letters to Mary Virginia Foreman. Like a diary, they chronicle Schnabel“s career after he had left Germany, the catastrophe of World War II and its bitter consequences, and his ideas about the arts, politics, and the academic research of his time.

The issues seem astonishingly relevant to the present-day reader: the survival of the arts in an environment defined almost exclusively by economic considerations; the goals of e...